Road Surface Roughness

[BeeUU]

This may seem trivial but the other day I was thinking how much does the road surface play into efficiency. I guess this falls into the same area as water spray in the rain. Is this another reason to "ride the rails" on the road. I know I have started.

The noise level is certainly higher, thus there is more energy spent creating that sound as the tires flex over the surface. Not to mention pot holes and patches.

I do not have a scan gauge to test this out, is there anyone out there willing to try?

Every little bit counts.

Many thanks!!!

[rh77]

On an unofficial basis, I've noticed the ability to coast further on asphalt -- so less friction = better FE, for example

-New asphalt is the best (but doesn't last as long as concrete)
-Concrete isn't as good -- seems to take more energy to push the tires over the surface's imperfections (but last longer, is more expensive to pave)
-Worn concrete gets smooth, but the expansion gaps between sections take a beating over time and create friction-robbing bumps, that are generally sealed with asphalt.
-"Chip and Seal" has to be the worst as it's nearly like gravel when new, but smooths-out as it wears down to the tar
-Gravel is the worst with FE, but the most fun
-No offense up there, but Iowa has the loudest, roughest Interstates. I don't know what they use but I believe "Car and Driver" mentioned the same once (and I agree from experience).

Fun Fact: Sections of Washington State's Interstate Highway System still has some of the original pavement from almost 50 years ago (due to the granite-like quality of the stone used from local quarries).

[zpiloto]

Here's a site that I've used for cycling. if you look to the tool bar to the right it gives the Coefficient of Rolling Resistance for different road types. So yes there is a difference in types.

On the bike which would also translate to the car. On a wet road the painted lines offer less resistance then the unpainted parts. Roads have a crest for drainage so the top is the place to be when wet. Is it enough to make a difference? "Shrug"

[ELF]

Originally Posted by zpiloto

"Shrug"

Hey, do you have SVOboys permission to use that word? I think owns the rights to that

I do a lot of roller blading in the summer, big difference in rolling resistance between different surfaces. Smoothed out older concrete is the best followed closely by new blacktop.

[zpiloto]

Originally Posted by ELF

Hey, do you have SVOboys permission to use that word? I think owns the rights to that

I was not aware that he owned it but after looking at his avatar I see the word *shrug* not "shrug". I've had a battery of $500/hour solicitors look at it and they assure me that there is no infringement but for the harmony of the boards and my respect for SVOboy I will refrain from it's further use.

[Peakster]

Saskatchewan has a vast abundance of gravel roads and I will tell you that the MPG impact is destructive. I usually lower my speed by a good 5-10mph on gravel and STILL get less mpg than if I was going faster on paved roads. I haven't really tested any true Scanguage readings but I remember one trip I was getting ~49mpg @ 50mph on paved highway, and then ~43mpg on a gravel road in the same direction when travelling at around 45mph.

Gravel roads = MPG death.

[Mike T]

Originally Posted by rh77

Fun Fact: Sections of Washington State's Interstate Highway System still has some of the original pavement from almost 50 years ago (due to the granite-like quality of the stone used from local quarries).

Tell me about it, I was "enjoying" some of these 50 year old concrete sections on I-5 last weekend in my smart, when my wife and I went to Seattle for the day and a dinner date. There are some bits of I-90 to the east of the Columbia River that are really poor too.

[psyshack]

Smooth concrete or asphalt,,, I cant tell the diff.

Course asphalt is a killer. And whats up with all this fine grooving they are doing on concrete hwy's here in Oklahoma... The tiny grooves suck big time.

[BeeUU]

Originally Posted by rh77

Fun Fact: Sections of Washington State's Interstate Highway System still has some of the original pavement from almost 50 years ago (due to the granite-like quality of the stone used from local quarries).

Yea, I get to drive on that nastiness all the time and is the reason I thought I started this thread, the vibrations and noise rattled the question out of my head!!

The problem is between the granite the cement is missing, mostly due to the studded snow tires that are allowed in the winter. In addition to the rough surface grooves are worn in the surface where the water pools when it rains. It rains a little bit in Seattle so you get troughs of water. Nice.

Plus, as you mention, the expansion strips are raised shake the #$% out of the car at speed. That really hurts.

Thanks for the comments.....

[BumblingB]

A few years ago I took a trip in my Insight to TX. On the way back we decided to take backroads America - TX to FL. When I went from the nice two lane roads of TX to garbage 2 lane roads of LA my FCD (fuel consumption display for newbies) went from a constant 100 MPG to around 60. It stayed there until we made it to better road.

While conversing on a hybrid website, I argued that in my plea as to why I got such cruddy mileage (avg went down to around 58) on my trip and was told I should be able to get great mileage no matter what. IMO shallow hills kill mileage too, I had those and the the bad road on that trip even though I was travelling in the car's "sweet speed" area - 50mph. Still that 50mph only yeilded 58mpg.

Short answer - YES - IMO bad/rough roads murder mileage.